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You searched for: creator:Matthew Josephson
[texts]Josephson vortex lattice in layered superconductors - Alexei E. Koshelev
Many superconducting materials are composed of weakly coupled conducting layers. Such a layered structure has a very strong influence on the properties of vortex matter in a magnetic field. This review focuses on the properties of the Josephson vortex lattice generated by the magnetic field applied in the layers direction. The theoretical description is based on the Lawrence-Doniach model in the London limit which takes into account only the phase degree of freedom of the superconducting order p...
Downloads: 5
[texts]Fate of the Josephson effect in thin-film superconductors - Michael Hermele
The dc Josephson effect refers to the dissipationless electrical current -- the supercurrent -- that can be sustained across a weak link connecting two bulk superconductors. This effect is a probe of the fundamental nature of the superconducting state. Here, we analyze the case of two superconducting thin films connected by a point contact. Remarkably, the Josephson effect is absent at nonzero temperature, and the resistance across the contact is nonzero...
Downloads: 2
[texts]1/f Flux Noise in Josephson Phase Qubits - Radoslaw C. Bialczak
We present a new method to measure 1/f noise in Josephson quantum bits (qubits) that yields low-frequency spectra below 1Hz. Comparison of noise taken at positive and negative bias of a phase qubit shows the dominant noise source to be flux noise and not junction critical-current noise, with a magnitude similar to that measured previously in other systems. Theoretical calculations show that the level of flux noise is not compatible with the standard model of noise from two-level state defects in...
Downloads: 1
[texts]On the Josephson effect in a Bose-Einstein condensate subject to a density dependent gauge potential - Matthew Edmonds
We investigate the coherent dynamics of a Bose-Einstein condensate in a double well, subject to a density dependent gauge potential. Further, we derive the nonlinear Josephson equations that allow us to understand the many-body system in terms of a classical Hamiltonian that describes the motion of a nonrigid pendulum with an initial angular offset. Finally we analyze the phase-space trajectories of the system, and describe how the self-trapping is affected by the presence of an interacting gaug...
Downloads: 6
[texts]Lifetime and Coherence of Two-Level Defects in a Josephson Junction - Yoni Shalibo
We measure the lifetime ($T_{1}$) and coherence ($T_{2}$) of two-level defect states (TLSs) in the insulating barrier of a Josephson phase qubit and compare to the interaction strength between the two systems. We find for the average decay times a power law dependence on the corresponding interaction strengths, whereas for the average coherence times we find an optimum at intermediate coupling strengths...
Downloads: 16
[texts]Vortex matter in layered superconductors without Josephson coupling: numerical simulations within a mean-field approach - Hans Fangohr
We study vortex matter in layered superconductors in the limit of zero Josephson coupling. The long range of the interaction between pancake vortices in the c-direction allows us to employ a mean-field method: all attractive inter-layer interactions are reduced to an effective substrate potential, which pancakes experience in addition to the same-layer pancake repulsion. We perform numerical simulations of this mean-field model using two independent numerical implementations with different simul...
[texts]High-fidelity gates in a Josephson qubit - Erik Lucero
We demonstrate new experimental procedures for measuring small errors in a superconducting quantum bit (qubit). By carefully separating out gate and measurement errors, we construct a complete error budget and demonstrate single qubit gate fidelities of 0.98, limited by energy relaxation. We also introduce a new metrology tool -- a Ramsey interference error filter -- that can measure the occupation probability of the state $\ket{2}$ down to $10^{-4}$, a magnitude near the fault tolerant threshol...
Downloads: 2
[texts]Defect-Unbinding Transition in Layered Superconductors - Matthew J. W. Dodgson
We establish a new interstitial-vacancy unbinding transition of the Berezinskii-Kosterlitz-Thouless type, transforming the three dimensional pancake vortex lattice of a decoupled layered superconductor into a defected solid. This transition is the natural finite-field extension of the vortex-anti-vortex unbinding transition establishing the zero-field superfluid stiffness. At finite Josephson coupling, the defect unbinding transition turns into a topological decoupling transition.
Downloads: 11
[texts]State tomography of capacitively shunted phase qubits with high fidelity - Matthias Steffen
We introduce a new design concept for superconducting quantum bits (qubits) in which we explicitly separate the capacitive element from the Josephson tunnel junction for improved qubit performance. The number of two-level systems (TLS) that couple to the qubit is thereby reduced by an order of magnitude and the measurement fidelity improves to 90%. This improved design enables the first demonstration of quantum state tomography with superconducting qubits using single shot measurements.
Downloads: 5
[texts]Detecting fractions of electrons in the high-$T_c$ cuprates - T. Senthil
We propose several tests of the idea that the electron is fractionalized in the underdoped and undoped cuprates. These include the ac Josephson effect, and tunneling into small superconducting grains in the Coulomb blockade regime. In both cases, we argue that the results are qualitatively modified from the conventional ones if the insulating tunnel barrier is fractionalized. These experiments directly detect the possible existence of the chargon - a charge $e$ spinless boson - in the insulator...
Downloads: 3
[texts]First-order sideband transitions with flux-driven asymmetric transmon qubits - J. D. Strand
We demonstrate rapid, first-order sideband transitions between a superconducting resonator and a frequency-modulated transmon qubit. The qubit contains a substantial asymmetry between its Josephson junctions leading to a linear portion of the energy band near the resonator frequency. The sideband transitions are driven with a magnetic flux signal of a few hundred MHz coupled to the qubit. This modulates the qubit splitting at a frequency near the detuning between the dressed qubit and resonator ...
Downloads: 7
[texts]Dynamics of superconducting nanowires shunted with an external resistor - Matthew W. Brenner
We present the first study of superconducting nanowires shunted with an external resistor, geared towards understanding and controlling coherence and dissipation in nanowires. The dynamics is probed by measuring the evolution of the V-I characteristics and the distributions of switching and retrapping currents upon varying the shunt resistor and temperature. Theoretical analysis of the experiments indicates that as the value of the shunt resistance is decreased, the dynamics turns more coherent ...
Downloads: 2
[texts]Microwave Spectroscopy of a Cooper-Pair Transistor Coupled to a Lumped-Element Resonator - Matthew T. Bell
We have studied the microwave response of a single Cooper-pair transistor (CPT) coupled to a lumped-element microwave resonator. The resonance frequency of this circuit, $f_{r}$, was measured as a function of the charge $n_{g}$ induced on the CPT island by the gate electrode, and the phase difference across the CPT, $\phi_{B}$, which was controlled by the magnetic flux in the superconducting loop containing the CPT...
Downloads: 10
[texts]Dissipative Chaos in Semiconductor Superlattices - Kirill N. Alekseev
We consider the motion of ballistic electrons in a miniband of a semiconductor superlattice (SSL) under the influence of an external, time-periodic electric field. We use the semi-classical balance-equation approach which incorporates elastic and inelastic scattering (as dissipation) and the self-consistent field generated by the electron motion. The coupling of electrons in the miniband to the self-consistent field produces a cooperative nonlinear oscillatory mode which, when interacting with t...
Downloads: 8
[texts]Universal point contact resistance between thin-film superconductors - Michael Hermele
A system comprising two superconducting thin films connected by a point contact is considered. The contact resistance is calculated as a function of temperature and film geometry, and is found to vanish rapidly with temperature, according to a universal, nearly activated form, becoming strictly zero only at zero temperature. At the lowest temperatures, the activation barrier is set primarily by the superfluid stiffness in the films, and displays only a weak (i.e., logarithmic) temperature depend...
Downloads: 3
[texts]Memoirs Of Egotism - Josephson, Matthew

Downloads: 132
[texts]THE PRESIDENT MAKERS THE CULTURE OF POLITICS AND LEADERSHIP IN AN AGE OF ENLIGHTENMENT 1896-1919 - MATTHEW JOSEPHSON

Downloads: 437
[texts]Sidney Hillman Statesman Of American Labor - Matthew Josephson

Downloads: 854
[texts]The Last Lady (Volume 17) - Josephson, Matthew
"The Last Lady" is an article from Poetry, Volume 17. View more articles from Poetry.View this article on JSTOR.View this article's JSTOR metadata.You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-20572814
Downloads: 19
[texts]THE PRESIDENT MAKERS THE CULTURE OF POLITICS AND LEADERSHIP IN AN AGE OF ENLIGHTENMENT 1896-1919 - MATTHEW JOSEPHSON

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